Definition: In this task, you are given an input list A. You need to convert all the alphabets in the list with a number representing their position in the English alphabet. E.g., replace A by 1, B by 2, a by 1, b by 2, and so on.
Input: ['5913', '6135', '4167', 'S', '9777', 'S']

5913, 6135, 4167, 19, 9777, 19